Plasmatron fuel converters reform hydrocarbons to generate a hydrogen rich gas through the use of plasma discharges. (See, for example, U.S. Pat. Nos. 6,322,757 and 5,887,554, the teachings of which are incorporated herein by reference). Two general types of plasma discharge regimes can be distinguished by their electrical characteristics and their modes of operation. A non-arcing discharge regime operates at high voltage and low currents, while an arc discharge regime operates at low voltage and high currents. (For a general treatise, see J. Reece Roth, Industrial Plasma Engineering, Vol. 1 and 2 , Institute of Physics: Bristol, UK, 1995).
Thermal arc plasmatrons have received particular attention in the prior art. (See, for example, U.S. Pat. Nos. 5,425,332 and 5,437,250, the teachings of which are incorporated herein by reference). These thermal arc plasmatrons operate at low voltage and high current and, therefore, have relatively inefficient electrical power to chemical power conversion ratios. Better electrical power to chemical power conversion ratios, as well as lower current resulting in lower electrode erosion, can be obtained through the use of non-arcing discharge plasmatrons. However, non-arcing discharges are usually operable at sub-atmospheric pressure, typically less than about 20 Torr. When pressure is increased, the non-arcing discharge rapidly transitions to an arc discharge. Low pressure gas glow discharges and apparatus for their production are known. (See, for example, U.S. Pat. Nos. 2,787,730; 3,018,409; 3,035,205; 3,423,562; 4,830,492; 4,963,792; and 4,967,118, the teachings of which are incorporated herein by reference). However, the effective volumetric flow rates through these low pressure devices are limited.
It is desirable to have a plasma converter that produces discharges in the non-arcing regime in a substantially continuous manner with a substantially enlarged effective discharge volume.